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By pass ratio in a turbine engine is the ratio of the ? [ Progression visibility ]

Question 46-1 : Cold air mass flow to the hot air mass flow speed of the combusted air to the speed of the by pass air intake air pressure to the turbine delivery air pressure tertiary air mass flow to the primary air mass flow

Img939.bypass ratio = bypass mass flow / hp compressor mass flow .by pass mass flow is cold air mass flow .hp compressor mass flow is the hot air mass flow exemple 146 Cold air mass flow to the hot air mass flow.Cold air mass flow to the hot air mass flow.

On landing and prior to shut down a gas turbine engine should be run at 'ground ?

Question 46-2 : The core temperature to diminish the turbine blade temperature to reduce only the engine to be compressor washed cool oil flushing of bearings particularly those in the turbines

exemple 150 The core temperature to diminish.The core temperature to diminish.

Both gas turbine and piston engines utilise a cycle of induction compression ?

Question 46-3 : I continuous ii constant pressure i continuous ii constant volume i intermittent ii constant pressure i intermittent ii constant volume

Piston engine the combustion process is intermittent governed by the rythm of the back and forth movements of the piston in a cylinder the combustion occurs at constant volume in the cylinder .turbine engine the combustion process is continuous and occurs at constant pressure exemple 154 (i) continuous (ii) constant pressure(i) continuous (ii) constant pressure

For a subsonic airflow in a divergent duct the ?

Question 46-4 : Pressure increases velocity decreases and temperature increases pressure decreases velocity increases and temperature increases pressure increases velocity decreases and temperature decreases pressure decreases velocity increases and temperature decreases

exemple 158 Pressure increases, velocity decreases and temperature increases.Pressure increases, velocity decreases and temperature increases.

An engine pressure ratio epr can be defined as the ratio of ?

Question 46-5 : Jet pipe total pressure to compressor inlet total pressure jet pipe total pressure to combustion chamber pressure combustion chamber pressure to compressor inlet total pressure compressor outlet pressure to compressor inlet total pressure

Epr is defined as the ratio of the total turbine outlet pressure to the total compressor inlet pressure . 947.'total turbine outlet pressure' is 'jet pipe total pressure' exemple 162 Jet pipe total pressure to compressor inlet total pressure.Jet pipe total pressure to compressor inlet total pressure.

For a fan jet engine the by pass ratio is the ?

Question 46-6 : Cold air mass flow divided by the hot air mass flow hot air mass flow divided by the cold air mass flow hot air mass flow divided by the fuel flow fuel flow divided by hot air mass flow

Img939.bypass ratio = bypass mass flow / hp compressor mass flow .by pass mass flow is cold air mass flow .hp compressor mass flow is the hot air mass flow exemple 166 Cold air mass flow divided by the hot air mass flow.Cold air mass flow divided by the hot air mass flow.

The by pass air in a by pass type gas turbine engine promotes lower specific ?

Question 46-7 : Decrease in exhaust gas flow average velocity and higher propulsive efficiency decrease in combustion chamber temperature and higher thermal efficiency increase in exhaust gas flow average velocity thus increasing engine pressure ratio increase in the mean jet temperature and increase in thermal efficiency

Bypass engines have a number of advantages . the bypass air does not need to be combusted to achieve its acceleration since no fuel is needed to heat the air the design is inherently more thermally efficient . the bypass air is given a smaller acceleration so its propulsive efficiency is greater at lower speeds .the reason that answer decrease in combustion chamber temperature and higher thermal efficiency is not correct is that although the engine is more thermally efficient combustion chamber temperatures are not reduced exemple 170 Decrease in exhaust gas flow average velocity and higher propulsive efficiency.Decrease in exhaust gas flow average velocity and higher propulsive efficiency.

In the airflow through a single spool axial flow turbo jet engine the axial ?

Question 46-8 : On exit from the propelling nozzle as it leaves the compressor within the combustion chamber as it leaves the turbine

Single spool axial flow turbo jet engine . 912.the term 'single spool' refers to the fact that there is only one shaft this shaft connects one turbine section to one compressor section .all jet engines in current use are axial flow engines meaning that the compression phase is done axially parallel to the axis of the engine as the air flows through the compressor .axial flow engines are different from early jet engines which compressed air in a centrifugal compressor .the axial velocity of the air is greatest on exit from the propelling nozzle exhaust of the propulsive gases exemple 174 On exit from the propelling nozzle.On exit from the propelling nozzle.

In a jet engine the propelling nozzle ?

Question 46-9 : Must be designed to obtain the correct balance of pressure and velocity to prevent flow separation reduces noise directs the hot gas stream onto the turbine at the optimum angle of attack decreases the velocity and increases the pressure in the jet pipe to provide greater thrust

exemple 178 Must be designed to obtain the correct balance of pressure and velocity to prevent flow separation.Must be designed to obtain the correct balance of pressure and velocity to prevent flow separation.

In a multi spool turbofan engine the fan is driven by ?

Question 46-10 : The rearmost turbine the intermediate turbine the foremost turbine all three turbines since they are on a common shaft with the compressor

The high pressure turbine drives the high pressure compressor .the low pressure turbine drives the fan and the low pressure compressor . 948.therefore we can say that the fan is driven from the rearmost turbine by a shaft

After air has passed through the compressor of a gas turbine engine the ?

Question 46-11 : Temperature will be higher than the inlet temperature velocity will be higher than the inlet velocity pressure will be the same as the inlet pressure velocity will be the same as the inlet velocity

Compression of air generates heat the air is warmer after compression .1 compressed air high pressure flows toward low pressure.2 the compressor sections are in the front of the engine and the turbine in the rear.3 the compressors are attached to the turbines via shafts.4 between the compressor and turbine sections is the combustion chamber where fuel is mixed with the compressed air and iginited .the compressor section is made up of alternating rows rotating blades and stationary vanes that are shaped like wings curved on one side and flat on the other and they function like wings too airflow creates low pressure on the curved side high pressure on the flat this imparts the direction of the airflow toward the rear of the engine high pressure flows toward low pressure .the leading edges of these rotating blades face the leading edge of the stationary blades and as the air cascades through each pair of rotor and stationary vanes it becomes more and more compressed .the air enters the combustion chamber and is rapidly heated and wants to expand but there is only so much room for expansion which is another form of compression so it continues to the rear of the engine where the pressure is lower and it meets the turbines the turbine are like pinwheels the fast flowing compressed air strikes the turbines and causes it them to spin .add more fuel for more heat the compressed air expands faster and the turbines spin faster because they are attached to the compressor section via shaft the compressor spins faster too which compresses incoming air faster and even more .air does not like to be compressed it likes to be in its normal state so it roars past the turbines out the back of the engine and the reaction thrust of the exhaust against the engine itself causes the propulsion exemple 186 Temperature will be higher than the inlet temperature.Temperature will be higher than the inlet temperature.

To achieve reverse thrust on a turbine engine with a high by pass ratio ?

Question 46-12 : The fan flow is deflected the fan is stopped the direction of rotation of the fan is reversed the flow of hot stream air is reversed

An aircraft flying in conditions of continuous heavy rain and high ambient ?

Question 46-13 : Engine igniters airframe de icing only engine intake anti icing only both engine intake anti icing and airframe de icing

Normally in flight no igniters are in use as the combustion is self sustaining during engine start and for take off and landing igniters are in use .you have to use igniters in case of moderate or severe precipitation turbulence or icing or for an in flight relight exemple 194 Engine igniters.Engine igniters.

The engine type represented in the drawing is a . 951 ?

Question 46-14 : Twin spool turbofan single spool turbofan twin spool turbojet triple spool turbofan

exemple 198 Twin-spool turbofan.Twin-spool turbofan.

When the combustion gases pass through a turbine the ?

Question 46-15 : Pressure drops pressure rises axial velocity decreases temperature increases

exemple 202 Pressure drops.Pressure drops.

Regarding a jet engine .i the maximum thrust decreases as the pressure altitude ?

Question 46-16 : I is correct ii is correct i is incorrect ii is correct i is correct ii is incorrect i is incorrect ii is incorrect

.jet engines are more efficient at higher altitudes because less fuel is needed for a given thrust due to reduction in lift and drag and lower temperatures through the inlet cause a significant reduction in specific fuel consumption up to the tropopause .specific fuel consumption is the amount of fuel burnt per unit of thrust for jets it reduces with altitude up to the tropopause exemple 206 I is correct, ii is correct.I is correct, ii is correct.

Regarding a jet engine .i the maximum thrust increases as the pressure ?

Question 46-17 : I is correct ii is incorrect i is incorrect ii is correct i is correct ii is correct i is incorrect ii is incorrect

.jet engines are more efficient at higher altitudes because less fuel is needed for a given thrust due to reduction in lift and drag and lower temperatures through the inlet cause a significant reduction in specific fuel consumption up to the tropopause .specific fuel consumption is the amount of fuel burnt per unit of thrust for jets it reduces with altitude up to the tropopause exemple 210 I is correct, ii is incorrect.I is correct, ii is incorrect.

One of the advantages of an annular combustion chamber is ?

Question 46-18 : A reduced thermal stress on the turbine that fewer igniters are required a higher structural strength a simpler assembly

A combustion chamber is a very complex structure with its divergent convergent passages compare to old multi can combustion system annular combustion chamber are shorter lighter cheaper with improved combustion characteristics more power and greater efficiency the main driver in combustion chamber development is the need to equalise temperature and flow around the whole turbine entry ring in order to reduced thermal stress exemple 214 A reduced thermal stress on the turbine.A reduced thermal stress on the turbine.

The correct order of decreasing freezing points of the three mentioned fuels is ?

Question 46-19 : Jet a jet a 1 jet b jet b jet a 1 jet a jet a 1 jet a jet b jet b jet a jet a 1

The accepted minimum fuel temperature for safe flight for .jet a is 40°c.jet a 1 is 47°c.jet b is 65°c exemple 218 Jet a, jet a-1, jet b.Jet a, jet a-1, jet b.

Labyrinth seals in the lubrication system of a gas turbine engine are designed ?

Question 46-20 : Not completely tight allowing some movement between rotating and static parts not completely tight allowing only some radial movement between rotating and static parts completely tight allowing no movement between rotating and static parts completely tight allowing some axial movement between rotating and static parts

exemple 222 Not completely tight, allowing some movement between rotating and static parts.Not completely tight, allowing some movement between rotating and static parts.

Regarding a jet engine .i the maximum thrust decreases as the pressure altitude ?

Question 46-21 : I is correct ii is correct i is incorrect ii is correct i is correct ii is incorrect i is incorrect ii is incorrect

Jet engines are more efficient at higher altitudes because less fuel is needed for a given thrust due to reduction in lift and drag and lower temperatures through the inlet cause a significant reduction in specific fuel consumption up to the tropopause .specific fuel consumption is the amount of fuel burnt per unit of thrust for jets it reduces with altitude up to the tropopause exemple 226 I is correct, ii is correct.I is correct, ii is correct.

The characteristics of an axial compressor are .1 a low pressure ratio by ?

Question 46-22 : 1 3 1 4 2 3 3 4

Img914.the key word here is by stage a centrifugal compressor will produce about 5 1 ratio per stage ie impeller & diffuser compared to a axial that gives about 1 2 1 per stage however the use of multi stage axial compressors gives a bigger overall ratio exemple 230 1, 3.1, 3.

Which of the following statements is correct about the flow in a divergent ?

Question 46-23 : I is correct ii is correct i is incorrect ii is correct i is correct ii is incorrect i is incorrect ii is incorrect

There is a velocity decrease as air flows from a small inlet to a larger outlet exemple 234 I is correct, ii is correct.I is correct, ii is correct.

Which of the following statements is correct about the flow in a divergent ?

Question 46-24 : I is correct ii is correct i is incorrect ii is correct i is correct ii is incorrect i is incorrect ii is incorrect

In a divergent duct with subsonic flow the static pressure rises as does static temperature but the total temperature remains constant exemple 238 I is correct, ii is correct.I is correct, ii is correct.

Which of the following statements is correct about the flow in a divergent ?

Question 46-25 : I is correct ii is correct i is incorrect ii is correct i is correct ii is incorrect i is incorrect ii is incorrect

A flat rated turbofan engine has a constant maximum rated thrust level ?

Question 46-26 : Up to a specific oat up to a specific pressure altitude above a specific oat above a specific pressure altitude

.the term flat rating is so called because of the flat nature of thrust versus the ambient temperature curve the curve shows that from the lowest operating temperature possible to the specified temperature the engine produces full thrust above this temperature full thrust will not be permitted .a 'flat rated' turbofan engine is controlled in such a way that at constant ambient air pressure there is no variation of take off thrust with air temperature up to some specified temperature limit .above that limit the engine operates in such a way that either . the fan speed or the compressor speed is constant or . the turbine inlet temperature is constant.and in either case the thrust then decreases with increasing temperature exemple 246 Up to a specific oat.Up to a specific oat.

Which of the following statements is correct about the flow in a divergent ?

Question 46-27 : I is correct ii is incorrect i is incorrect ii is correct i is correct ii is correct i is incorrect ii is incorrect

exemple 250 I is correct, ii is incorrect.I is correct, ii is incorrect.

Which of the following statements is correct about the flow in a divergent ?

Question 46-28 : I is incorrect ii is incorrect i is incorrect ii is correct i is correct ii is incorrect i is correct ii is correct

The speed flow is reduced static pressure increases dynamic pressure decreases and total pressure remains unchanged there is no total temperature changes but static temperature increases while dynamic temperature decreases exemple 254 I is incorrect, ii is incorrect.I is incorrect, ii is incorrect.

Which of the following statements is correct about the flow in a divergent ?

Question 46-29 : I is incorrect ii is incorrect i is incorrect ii is correct i is correct ii is incorrect i is correct ii is correct

Static pressure increases dynamic pressure decreases and total pressure remains unchanged there is no total temperature changes exemple 258 I is incorrect, ii is incorrect.I is incorrect, ii is incorrect.

Which of the following statements is correct about the flow in a divergent ?

Question 46-30 : I is incorrect ii is incorrect i is correct ii is correct i is correct ii is incorrect i is incorrect ii is correct

Static pressure increases dynamic pressure decreases and total pressure remains unchanged there is no total temperature changes but static temperature increases while dynamic temperature decreases exemple 262 I is incorrect, ii is incorrect.I is incorrect, ii is incorrect.

Which statement is correct about the flow in a divergent jet engine inlet .i ?

Question 46-31 : I is incorrect ii is incorrect i is incorrect ii is correct i is correct ii is incorrect i is correct ii is correct

The flow speed decreases static pressure increases dynamic pressure decreases and total pressure remains unchanged exemple 266 I is incorrect, ii is incorrect.I is incorrect, ii is incorrect.

Which of the following statements is correct about the flow in a divergent ?

Question 46-32 : I is incorrect ii is incorrect i is incorrect ii is correct i is correct ii is incorrect i is incorrect ii is correct

Static pressure increases dynamic pressure decreases and total pressure remains unchanged there is no total temperature changes but static temperature increases while dynamic temperature decreases exemple 270 I is incorrect, ii is incorrect.I is incorrect, ii is incorrect.

Which of the following statements is correct about the flow in a divergent ?

Question 46-33 : I is incorrect ii is incorrect i is incorrect ii is correct i is correct ii is incorrect i is correct ii is correct

Static pressure increases dynamic pressure decreases and total pressure remains unchanged there is no total temperature changes but static temperature increases while dynamic temperature decreases exemple 274 I is incorrect, ii is incorrect.I is incorrect, ii is incorrect.

Both gas turbine and piston engines use a cycle made up of induction ?

Question 46-34 : I is correct ii is correct i is incorrect ii is incorrect i is incorrect ii is correct i is correct ii is incorrect

Piston engine the combustion process is intermittent governed by the rythm of the back and forth movements of the piston in a cylinder the combustion occurs at constant volume in the cylinder .turbine engine the combustion process is continuous and occurs at constant pressure exemple 278 I is correct, ii is correct.I is correct, ii is correct.

A twin spool engine with an inlet air mass flow of 220 kg/s and a hp compressor ?

Question 46-35 : 0 1 1 1 10

Img939.bypass ratio = bypass mass flow / hp compressor mass flow.220 220 = 0.0/220 = 0.bypass ratio = 0 exemple 282 0.0.

A turbofan engine with an inlet air mass flow of 200 kg/s and a hp compressor ?

Question 46-36 : 9 10 5 11

Img939.bypass ratio = bypass mass flow / hp compressor mass flow.200 20 = 180.180/20 = 9 exemple 286 9.9.

A turbofan engine with an inlet air mass flow of 220 kg/s and a hp compressor ?

Question 46-37 : 10 11 1 1 12

Img939.bypass ratio = bypass mass flow / hp compressor mass flow.220 20 = 200.200 / 20 = 10 exemple 290 10.10.

A turbofan engine with a bypass air mass flow of 200 kg/s and a hp compressor ?

Question 46-38 : 10 11 1 1 9

Img939.bypass ratio = bypass mass flow / hp compressor mass flow.200/20 = 10 exemple 294 10.10.

A turbofan engine with an inlet air mass flow of 220 kg/s and a bypass mass ?

Question 46-39 : 10 11 1 1 9

Img939.bypass ratio = bypass mass flow / hp compressor mass flow.220 200 = 20.200 / 20 = 10 exemple 298 10.10.

The throttle lever angle tla information of a fadec controlled gas turbine ?

Question 46-40 : To the electronic engine control unit by a direct electrical wiring connection to the hydro mechanical main engine control via cables and pulleys to a single dedicated channel of the fadec

Tla thrust lever angle indicates the position of the thrust lever in control stand from a reference point usually this is 0° when thrust lever is at idle and increases up to 40° when thrust lever is advanced to take off position .this thrust lever is connected by mechanical linkages to an electrical resolver synchro sensor called thrust lever angle resolver the resolver has a stator and rotor the angle of the rotor with respect to stator reference point changes as thrust lever is moved this angle is called thrust lever resolver angle tra .this resolver is connected to electronic engine control eec to control engine thrust for different positions of the thrust lever exemple 302 To the electronic engine control unit by a direct electrical wiring connection.To the electronic engine control unit by a direct electrical wiring connection.

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1799 Free Training Exam Other source study: Furious atpl examen 46